ci: Integrating CodeCov with NGO repo [develop]

[michalChrobot]

Recently CodeCov was improved to also work for GitHub.com repositories so we can finally update the configuration to upload our results. This PR should be merged after we will be done with ongoing release process because it may require some corrections in the way how CodeCov comments will work so I don't want to block any ongoing work

Backport

This is ported to develop-2.0.0 branch in https://github.com/Unity-Technologies/com.unity.netcode.gameobjects/pull/3474. Note that it will not affect develop-2.0.0 branch since the configuration is being taken from default branch (currently develop) but when in the future we will switch the default branch then the configuration will already be there